Concrete planing machine



Oct. 9, 1945. G. F. cRocK CONCRETE PLANING MACHINE 2 Sheets-Sheet lFiled March 16, 1942 glwucm Tow Patented Oct. 9, 1945 CONCRETE PLANINGMACHINE Gregory F. Crock, Atlanta, Ga., assignor to General FloorCompany, New York, N. Y., a

corporation of Delaware Application March 16, 1942, Serial No. 434,941

6 Claims.

My present invention relates to machines or implements for smoothing thesurfaces of slabs of freshly deposited concrete and embodies a number offeatures of great utility in the art to which the invention pertains.

A number of different types of implements for grading freshly depositedbodies of concrete, initially smoothing the surfaces thereof, furthersmoothing and densifying such surfaces, and finally finishing the sameby hand or machine driven trowels, have been designed, suggested andactually placed in operation. Customarily, the body of freshly depositedconcrete is first screeded or levelled off and subjected to an initialsmoothing operation and, in my companion application, Serial No.445,919, filed June 5, 1942, an effective concrete grading and smoothingimplement is disclosed. After a machine or implement of this type hasbeen used, and before final trowelling, it is now common practice toemploy a rotary float device, especially in the laying of concrete slabswithin buildings, such as floor slabs, where it is not practical toemploy concrete surfacing machines of the type which may be and areoften used in the laying of concrete highways. The present inventionrelates particularly to machines or implements designed and intended tobe used upon the surface of a slab which has already been subjected to alevelling and preliminary surfacing treatment, the

purpose being to further smooth and densify the surface and place it incondition for final trowelling, the machine being a substitute for arotary float but having capacity to perform substantially the samefunctions in a superior manner and at much less cost.

While in the details of its construction the machine may varyconsiderably without departure from the scope of the invention it mayconveniently comprise two elongated concrete surfac smoothing membersthe work-engaging undersurfaces of which are of novel conformation,together with means for effecting relative longitudinal reciprocatorymovement of such members, the arrangement being such that the,

smoothing members may be 'manipulated and transported as a unit. Themechanism is preferably so designed likewise that, when it is inoperation, both smoothing members will be longitudinally moved, neitherremaining stationary.

The work-engaging undersurface of each member is so designed that, whenthe implement is drawn manually forward over the surface of a body ofconcrete by a force applied normally to the direction of its length, theconcrete surface is subjected to what might be designated a trowellingaction, particles of the upper surface being successively subjected tothe action of two relatively inclined smoothing surfaces which are movedin a desired direction while reciprocating transversely to suchdirection of movement, this by reason of the novel conformation of theWorkengaging undersurfaces of the smoothing members. Each suchwork-engaging undersurface is convex, comprising two angularly disposedplane surfaces which meet in a line which is slightly inclined to thelongitudinal or major axis of the member. As such member is reciprocatedin the irection of its length or major axis, and is moved bodily in adirection normal to its length, each surface particle of the concreteover which the smoothing surface passes is contacted first by Oneinclined portion of the members undersurface and thereafter by thesecond inclined surface, both surfaces being preferably equally inclinedto the horizontal.

It is found that an implement so constructed will not only accomplishits intended functions in a superior manner and produce a high-graderesult, but will effect a substantial reduction in the cost of surfacingas compared with the results obtained when machines of other types areemployed to accomplish generally similar results. By reason of its lightweight, the novel conformation of the work-engaging surfaces of itssmoothing members and the manner in which these surfaces aresimultaneously reciprocated, the machine may be readily drawn forwardlyacross a concrete surface and the amount of effort required of itsoperator, per square yard of concrete surface, is remarkably low. It isreadily manipulated past columns and other obstructions and hence may beused in the interiors of buildings, despite its very considerablelength. Time is saved because of the rapidity with which a large area ofconcrete may be smoothed in a given time.

By way of example one embodiment of the invention will be disclosed,this embodiment being illustrated in the accompanying drawings in which:

Figurelis a top plan view of the implement or machine;

Figure 2 is a front elevation of the same; Figure 3 is a section on line3-3 of Figure 1; Figure 4 is a section on line 44 of Figure 1; Figure 5is a section on line 5-5 of Figure 3;

and

Figure 6 is a section on line 6-6 of Figure 1. The major elements of themechanism comprise the two smoothing members which are substantiallyidentical in construction and are indicated in the drawings by thenumerals l and II, respectively. The smoothing member ID may bedesignated the forward member and the mem-- ber may be designated therear member inasmuch as the member H] is closer than member II, to anoperator who is grasping handle bar l2, thelmplement being drawn by theoperator so grasping bar l2 in the direction indicated by the arrow A,Figure 1, to accomplish its intended functions. It will be observed fromFigure 4 that the side members l2a, of the handle extend downwardly andrearwardly from the cross bar l2 to the forward member Hi, the lowerends of the side members l2a being rigidly secured to member ID atspaced points, as indicated in Figures 1 and 4. The smoothing membersmay be formed in various ways and the specific man ner in which they areconstructed is of relative unimportance except insofar as thework-engaging undersurface of each is concerned. These undersurfaces areformed as elongated rectangul'ar metallic plates l3 and M, respectively.The undersurface of each' plate'is divided into two triangularly shapedrelatively inclined portions indicated at |3a, l3b, and Ma and Mb,respectively, these portions being similarly inclined to the horizontaland each meeting along a straight line which extends from one corner ofthe plate to the diagonally opposite corner, this diagonal line for theplate |3 being indicated by the numeral |3c in Figure 1 and thecorresponding line for the smoothing member being indicated at Me, thelines of intersection I30 and He being parallel to each other.

Superposed' upon each plate is a truss-like frame comprisinglongitudinally extending angle bars, suitable vertical members, and suchtruss or bracing members which may .be deemed to be essential to renderthe smoothing member as an entirety relatively inflexible and to givethe same the necessary strength. The two members are secured together bymeans which enables them to be manipulated by an operator as a unit, butwhich permits relative longitudinal reciprocation thereof. Any suitableconnecting means capable of accomplishing the desired results may beemployed for this purpose, that illustrated in the drawings includingpairs of spaced grooved rollers I6 carried" by the forward member NJ andlocated in trackways or rollways of the smoothing member As shown inFigure 5 the rollers l6 of each pair of grooved rollers are mounted uponthe oposite ends of an axle member I! which is in turn rigidly supportedin the position in which it is shown by a, frame which includes theparallel rods |8 each of which is secured at two points to the forwardmember ID. Adjacent flanges of parallel angle members 29 and 2|, formingportion of, or mounted on, the frame of smoothing member H, enter thegrooves of the series of rollers l6 and comprise confining trackways forthese rollers, permitting movement of the rollers longitudinally ofmember II, but preventing lateral dislodgment or displacement of therollers from the positions in which they are shown. By the connectionsthus described the two members are at all times connected to each otherfor simultaneous bodily movement in the direction of the arrow A, butare quite free to move longitudinally relatively to each other.

Any suitable means for efiecting relative longitudinal movement of thetwo smoothing members may be employed and in the drawings a gasolineengine 20 is illustrated, this engine being mounted upon a bed plate 2|and having a power output shaft 22 upon which a grooved pulley 23 isfixed. Pulley 23 is operatively connected to a disk 24, the periphery ofwhich is also grooved, by means of a V-belt 25. The disk 24 is fixed ona shaft 26 rotatably supported in bearing 21 mounted upon smoothingmember l0. Likewise fixed upon shaft 26 is a second grooved disk 28,disk 28 being operatively connected to a disk 29, disposed in the sameplane,

' by means of a second V-belt 3!]. Disk 29 is fixed uponv the end of ashaft 3| parallel to shaft 26 and rotatably supported in bearings 32mounted upon the smoothing member II]. An eccentric pin projectingforwardly from disk 29 is indicated at 35 and this pin is connected to asecond pin 36 projecting rearwardly from a bracket 31 mounted upon theframe of smoothing member H, by means of a link 38. By the drivingconnection described the power of motor 20 may be delivered to link 38and, as the disk 29 is revolved, the link i caused to deliver athrusting force on smoothing member tending to move this member in onedirection, and to thereafter exert a pull on such member in the oppositedirection. The reactions of these forces are, of course, transmittedthrough shaft 3| to the member l0 and, by reason of the fact thatmembers l9 and II have very nearly the same mass and have the sameextent of engagement with the underlying concrete, both members willreciprocate when the motor 29 is in operation, one member moving in onedirection while the second member is moving in. the opposite direction.By varying the weights of members 0 and or'modifying the areas of theirundersurfaces, or by varying both weights and undersurfaces, the extentof reciprocation of one member with respect to the other may bemodified. Motion of relative reciprocation may be interrupted withoutstopping the motor 20 by sliding the motor longitudinally along memberH) and to permit this the base plate 2| upon which the motor issupported is slidable and means is provided for adjusting itlongitudinally of member II] to tighten or loosen V-belt 25 as may bedesired.

The means for sliding the motor and establishing or breaking the drivingconnection to disk 24 may conveniently include the operating handle 49fixed on the end of shaft 4| rotatably mounted in bearings 42 secured tomember ID. Fixed on shaft 4| intermediate bearings 42 are arms 43 andthe free end of each arm 43 is connected to a bracket 44 mounted uponbed plate 2| by means of a link 45. It will be obvious that, by movementof operating handle 40 from its full line position to its dotted lineposition (Figure 6) the bed plate and motor will be moved in a directionto cause the pulley 23 to approach the disk 24, which results inloosening of the belt 25. The driving connection through belt 25 isrendered operative by placing lever 40 in the positionin which it isshown in full lines in Figure 6.

One or more operators may grasp the cross bar |2 of the handle and maydraw the machine in the direction of the arrow A over a previouslylevelled concrete surface at a speed which will be readily establishedby observing the results obtained. Very little force is needed to effectthe advance of the machine in this manner, ven though the smoothingmembers be relatively long and the area of contact of the unclersurfaceof these members with the concrete relatively large. The implement is ofgreat utility, producing an improved smoothing effect, preparatory tofinal trowelling, at a less cost than that involved in the operation ofenerally similar implements of types heretofore suggested or used. Itmay be most conveniently manipulated indoors but, of course, may beemployed if desired in the laying of roadways or concrete slabsgenerally.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. Means for smoothing the surface of a freshly formed concrete floorslab or the like comprising an elongated member adapted to belongitudinally reciprocated while it is advanced over the slab surfacein a direction normal to its length, the work-engaging undersurfacethereof having two relatively inclined generally flat areas whichintersect along a line extending longitudinally of the said member andslightly inclined to the longitudinal axis thereof and neither of whichareas is horizontally disposed when said member is positioned to smooththe horizontal surface of a slab.

2. A concrete smoothing member having an elongated work-engagingundersurface, said undersurface comprising two relatively inclinedportions which intersect along a substantially straight line slightlyinclined to the major axis of said member both portions of saidundersurface being slightly inclined to the horizontal when said memberis positioned to smooth the horizontal surface of a slab.

3. The concrete smoothing member described in claim 2 in which saidundersurface is rectangular and the two portions thereof triangular, theline of intersection extending from one corner of said surface to thediagonally opposed corner.

4. Concrete surfacing mechanism comprising in combination, parallelelongated Work-engaging members the undersurface of each of which is, insection, formed as a down-pointed V, having a ridge extending diagonallyto the length thereof and said ridges being parallel, and means forlongitudinally reciprocating said members.

5. The combination set forth in claim 4 in which the undersurfaces ofeach member, on both sides of the diagonal ridge thereof, are relativelyinclined and make equal angles with the horizontal.

6. The combination set forth in claim 4 in which the means forlongitudinally reciprocating the said members is supported directly uponsaid members and is designed and constructed to effect simultaneousreciprocation of said members.

GREGORY F. CROCK.

